Effects of water on epoxy cure kinetics and glass transition temperature utilizing molecular dynamics simulations |
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| Authors: | Nathan Sharp Chunyu Li Alejandro Strachan Douglas Adams R Byron Pipes |
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| Institution: | 1. Department of Aeronautical EngineeringPurdue University, West Lafayette, Indiana 47907;2. Department of Materials EngineeringPurdue University, West Lafayette, Indiana 47907;3. Department of Civil Engineering, Vanderbilt University, Nashville, Tennessee |
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| Abstract: | Effects of water on epoxy cure kinetics are investigated. Experimental tests show that absorbed water in an uncured bisphenol‐F/diethyl‐toluene‐diamine epoxy system causes an increase in cure rate at low degrees of cure and a decrease in cure rate at high degrees of cure. Molecular simulations of the same epoxy system indicate that the initial increase in cure rate is due to an increase in molecular self‐diffusion of the epoxy molecules in the presence of water. Effects of water on the glass transition temperature (Tg) of the crosslinked thermoset are also studied. Both experiments and simulations show that water decreases Tg. Both types of results indicate that Tg effects are small below 1% water by weight, but that Tg depression occurs much quickly with increasing water content above 1%. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1150–1159 |
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| Keywords: | cure kinetics curing of polymers epoxy glass transition temperature molecular dynamics water |
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